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Steel Moment Connection Bolt Count Calculator

Calculate the number of bolts needed in a moment connection's bolt group to resist an applied moment.

Computed in your browser — nothing you enter is uploaded. Figures are presented for United States against IRC 2024, and every formula is cited under regulatory standards below.

Last verified 2026-08-26 · v1.0.0

Market
Imperial · sales tax

Bolts needed

8 bolts

Check your inputs

A simplified equivalent-force method — a full moment connection design also checks bolt group eccentricity, prying action, and plate bending per AISC 360 Chapter J and should be verified by a structural engineer.

Equivalent force at bolt group
375 kN

With the figures above, the bolts needed comes to 8. The method behind this is well established, though site conditions and material batches will move it somewhat. This is calculated for United States and cites IRC 2024. Building in another market? Change the selector above so the units and code reference follow.

Add the equipment this sizes

This result is a specification — 8 bolts — not a quantity. Put the thing it sizes into your project: how many, what you call it, and your supplier’s price.

Preliminary estimate, not certified engineering. This tool produces an indicative quantity calculation for planning purposes only — it is not a certified structural analysis, a guaranteed material takeoff, or a substitute for building department approval. Always verify measurements on-site and have a licensed contractor or structural engineer review any load-bearing, code-sensitive, or safety-critical work before purchasing materials or starting construction. Spotted an arithmetic or standards error? Report it to contact@craftquantities.com with your inputs — confirmed fixes become pinned regression tests.

[Schema Verified] Computed in alignment with American Concrete Institute (ACI 318-19) formulas and International Residential Code (IRC 2024) spatial boundaries.

Regulatory standards & verification citations

  • Simplified moment-connection bolt force: equivalent force = applied moment ÷ effective lever arm between bolt rows; required bolts = ceil(equivalent force ÷ per-bolt rated shear/tension capacity)

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Most jobs need more than one number. Add the calculators you need next and they open right here, underneath this one — your figures stay on screen and nothing is lost to a page change.

Frequently asked questions

Is this a complete moment connection design check?
No — this is a simplified equivalent-force screening estimate only. A full moment connection design per AISC 360 Chapter J also checks bolt group eccentricity, prying action, and plate bending, and must be verified by a structural engineer before use.
How is the equivalent bolt-group force calculated?
The applied moment is divided by the effective lever arm between bolt rows, treating the bolt group as a simple force couple — this is a simplification, not a rigorous elastic or plastic bolt-group analysis.
Where does the per-bolt rated capacity come from?
Use the bolt's design shear or tension capacity for its specific grade and diameter, per AISC 360 or your applicable structural steel code — this calculator does not derive that value for you.